Improvement in derricks



B. FREEMAN.

Derrick.

No, 167,398, Patented Sept. 7, 1875.

INVENTOR N. PUERS. PHOTO-LITHOGRAPHEH, WASHINGTON D C (5F ONE-HALF HISRIGHT TO JAM VERMONT.

BARTON FREEMAN, OF EAST ATTLEBOROUGH, MASSACHUSETTS, ASSIGNOR I ESMOANERNEY, OF ATTLEBOROUGH,

IMPROVEMENT IN DERRICKS.

Specification forming part of Letters Patent No. 167,398, datedSeptember 7, 1875; application filed May 6, 1875.

do hereby declare that the following is a full,

clear, and exact description thereof, which, with the accompanyingdrawings forming part of this specification, will enable others skilledin the art to make and use the same.

Figure I shows my improved derrick in elevation. Fig. II is an enlargedview of the power-multiplying device. Fig. III is a top view of thesame.

Similar letters of reference indicate corresponding parts.

The object of the invention is to produce a simple device for liftingheavy weights by manual power, and also for lowering the same by asimple movement of the same device.

The nature of the invention consists in the peculiar arrangement oflever, pawl, ratchetwheel, and check-pawl with springs, so that in oneposition the check-pawl will prevent the chain-wheel from turningbackward, and in the other position the check-pawl is kept clear of theratchet-wheel, and allows the same and the chain-wheel to turn backwardand so lower the load, until the lever is raised to a given point, whenthe check-pawl engages with the ratchet-wheel again, and so holds theweight.

In the drawings, A is a long handspike or lever secured to the curvedlever 12. This curved lever is supported on the same shaft which issecured to the ratchet-wheel and chain-wheel, and which turns injournals made in the iron frame of the third leg of the derrick. G isthe ratchet-wheel, and l the chainwheel. These are preferably made inone piece, but can be made separately and secured to the same shaft, soas to act together. E is the check-pawl secured to the frame by a pin,on which it turns. f is a spring resting on the curved lever 12, andsecured to the rod K, having the end where it is secured to the rod Kturned up, as shown at i, so as to form a shoulder. g is a springsecured on the curved lever 12 close to the pawl d. The blocks and fallsare of the usual construction, made so as to sustain heavy weights, thechain from which passes over the chain-wheel l. When a heavy weight issecured to the lower hook of the block and fall, and the long lever A israised, the pawl 01 passes over the ratchet-wheel G, and when the leveris lowered the pawl engages with the ratehet-wheel, and turns the same,and also the chain-wheel l, and thus exerts a strain upon the chain, andthrough the same a corresponding but greater strain through the blockand fall upon the weight to be raised. By repeating the up-and-downmotion of the lever A the weight is raised to any desired height withinthe limits of the derrick. When the mass is to be lowered the rod K ispulled down until the spring f is in the position indicated by thebroken lines on Fig. II. By this motion the check-pawl E is raisedsufficient to clear the teeth in the ratchet-wheel C, as shown in dottedlines, and when the lever A is raised the ratchet-wheel O andchain-wheel 1 will turn and pay out the chain, thus lowering the masssuspended by the block and fall. As soon as the spring 9 reaches theturned-up part z' of the spring f it is pressed over, and thus allowsthe checkpawl to engage with the ratchet-wheel, while the spring g, inpassing over the turned-up end tof the spring f, disengages the pawl 01from the ratchet-wheel by lifting the pin in the side of the pawl 01,and thus raising the same over the edge of the tooth, and by depressingthe lever A the pawl engages with the tooth, and the spring f, beingreleased, again lifts the check'pawl E, thus allowing a heavy mass to beslowly and safely lowered. By the vertical movements of the handle a,causing the curved upper surface of the lever 12 to change the tensionof the spring f, the check-pawl E is automatically lifted from theratchet when the handle a is raised to back the chain-wheel, and it iscaused to engage with the teeth when the handle a is lowered to take afresh hold of the ratchet; the shoulder on the spring f causing thespring g to rise and lift the pawl from the ratchet, and

permit the handle a to be lowered while the check-pawl E holds theratchet, these two springs operating upon the pawls, and causing them toact like the escapements of a watch.

The whole operation of raising and lowering a heavy mass may beperformed by one person without moving from his position at the end ofthe lever.

Stumps may be effectually pulled by this derrick by one man; and thesame device may be arranged to form a part of other hoistingmachines forraising heavy masses and lowering the same by manual power, the samebeing strong, efficient, and simple in construction and manipulation.

Having thus described my invention,Iclain1 as new and desire to secureby Letters Patent v The combination, in a derrick, of the lever A, thecurved lever b, the pawl 01, check-pawl E, and ratchet-wheel O with thesprings g and f and rod K, the whole operating together substantially asand for the purpose set forth.

- BARTON FREEMAN. Witnesses:

JOSEPH A. MILLER,

WM. 0. CHASE.

